204 DR. G. S. BRADY ON THE [Feb. 1, 



but the figure of the caudal ramus does not agree very accurately 

 with his description of it as being " almost straight." 



For this species I can at present only specify with certainty 

 a few localities in the West of Scotland : — lochs near Dumfries, 

 Lochmaben, Loch Fadd, and lochs in Lewis. 



Candona lactea Baird. (Plate XXIV. figs. 1-4.) 



1850. Candona lactea Baird, Proc. Zool. Soc. Lond. p. 255, 

 pi. xviii. (Annulosa) figs. 25-27. 



"1866. Candona lactea &, Candona detecta Brady, (1) pp. 382, 384. 



1889. Candona lactea Brady & Xorman, (2) p. 100. 



Female. — Length 0*75 mm. Shell seen from the side oblong 

 (fig. 1), subreniform, greatest height in the middle and equal to 

 rather less than one half of the length, extremities well rounded 

 and about equal in width ; dorsal margin straight or very feebly 

 arched, ventral almost straight, the median sinuation being scarcely 

 perceptible : seen from above (fig. 2) oblong, subovate, abruptly 

 acuminate in front, rounded oft' behind, width scarcely equalling 

 half the length. Shell-surface smooth, very finely and closely 

 punctated, colour white. Valves equal in size, bordered throughout, 

 except on the hinge-line, with a wide, thick lip which is destitute 

 of the pitted sculpture of the general shell-surface but is marked 

 by numerous transverse hair-like lines (fig. 3) : this appearance is, 

 however, seen only in the separated valves and best when viewed 

 by transmitted light. It forms a good diagnostic character. 



This species has not to my knowledge been noticed by any 

 Continental author. It may possibly have been sometimes 

 mistaken for the young of G. Candida, from which, however, it 

 may be at once separated by its evenly rounded extremities and 

 flattened dorsal surface. Nor have I noticed in C. Candida the 

 delicate pitting of the shell surface which may always be found 

 in C. lactea. The soft parts do not disclose any noteworthy 

 characters : the limbs — antennas especially — are short and stout. 

 The male has not been seen. The species is common every- 

 where in Britain. 



Candona pragilts Hartwig. (Plate XXIV. figs. 5-10.) 



1898. Candona fragilis Hartwig, Zool. Anzgr. p. 474. 



1900. „ „ G.W. Midler, (5) p. 31, pi. vii. figs. 8-11, 



14, 17, 19. 



Shell seen laterally oblong, subreniform (fig. 5), greatest height 

 situated in the middle, equal to less than half the length ; dorsal 

 margin evenly arched, ventral slightly sinuated in the middle ; 

 extremities nearly equal in width and well rounded : seen dorsally 

 the shell is compressed, oblong . (fig. 6), widest in the middle, with 

 equally tapered acuminate extremities, width scarcely equal to one 

 third of the length. Shell very thin and fragile ; surface smooth, 

 colourless ; the extremities slightly fringed with fine hairs. 

 Length 1 mm. The feet of the last pair are non-forcipate and 

 bear three apical setae, one of which is extremely long (fig. 9) : .the 



